Radiobiology 2

Question 1

What does BED mean?

Answer 1

ratio of a and b in linear quadratic model to quantify fractionation sensitivity.

Question 2

What does EQD2?

Answer 2

Equivalent total dose in 2 Gy

Question 3

What is accelerated repopulation?

Answer 3

Treatment with any cytotoxic agent can trigger surviving cells in a tumour to divide faster than before

Question 4

What happens if treatment is too long?

Answer 4

may compromise late fractions and trigger rapid repopulation

Question 5

What the four types of fractionation?

Answer 5

Standard
Hyperfractionation
Hypofractionation
Accelerated fractionation

Question 6

What are the advantages to prolonging treatment?

Answer 6

Spare early reactions and allow reoxygenation in tumours

Question 7

What can excessive prolongation due?

Answer 7

Decrease the acute reactions and without sparing late reactions

Allows cells to proliferate during treatment

Question 8

What is the rationale for Hyperfractionation?

Answer 8

Increase cell redistribution and re oxygenation

• Possible lower OER
• Different sparing of late reacting normal tissues

Question 9

What is the accelerated treatment criteria?

Answer 9

reduce repopulation

Question 10

What are unscheduled Interruptions?

Answer 10

Machine and staff availiability

• Public holidays
• Transport problems
• Medical problems
• social circumstance

Question 11

Considerations for retreatment?

Answer 11

Dose and volume
Chemotherapy
]Time elapsed since treatment
Tissues and organs involved.
Can cause hotspots and coldspots